The Colorado River, seen from Hopi Point, in Grand Canyon National Park, Arizona, USA.

The Colorado River, seen from Hopi Point, in Grand Canyon National Park, Arizona, USA. Starting at least 5 to 17 million years ago, erosion by the Colorado River has exposed a column of distinctive rock layers, which date back nearly two billion years at the base of Grand Canyon. While the Colorado Plateau was uplifted by tectonic forces, the Colorado River and tributaries carved Grand Canyon over a mile deep (6000 feet), 277 miles long and up to 18 miles wide.